Cannabinoids are a specific class of psychoactive compounds present in Cannabis sativa. Cannabinoids are known to affect various systems and/or organs, the most important being the central nervous system and the cardiovascular system. Effects of cannabinoid intake include alterations in memory and cognition, euphoria and sedation. Cannabinoids also increase heart rate and vary systemic arterial pressure. Peripheral effects related to bronchial constriction, immunomodulation, and inflammation have also been observed. The ability of cannabinoids to reduce intraocular pressure and to affect respiratory and endocrine systems is also well known.
There are two main types of cannabinoid receptors, CB1 which is expressed mainly in the basal ganglia and the limbic system of the brain, the lungs, liver and kidneys and CB2 which is mainly expressed on T cells of the immune system and in hematopoietic cells.
Compounds that are agonists or antagonists of one or both of the cannabinoid receptors have been shown to provide a variety of pharmacological effects. See, e.g., Pertwee, R. G., PHARMACOL. THER., 74:129-180 (1997) and Di Marzo, V., TRENDS NEUROSCI., 21:521-528 (1998). For example, cannabinoid receptor ligands have been shown to have pharmacological effects on the central nervous system, the immune system and the endocrine system. Consequently, there is considerable need to develop compounds that act as cannabinoid receptor (e.g., CB2 receptor) ligands.